Surprise
by strawberrybrunette
Summary: After blowing up his chemistry teacher accidentally, Clark is horrified to learn that Lex is his substitute. Will Clark make it through the week with his sanity and secret in tact? Probably not. R
1. The Accident

Surprise!

AN: Mwahaha.

Disclaimer: Not mine.

o-o-o-o-

Clark Kent frowned in concentration at the Bunsen Burner in front of him. The idiotic thing simply refused to be lit. He had tried everything. He had checked the gas hose three times, turned the gas on and off countless times, and had used at least seven different sparkers in futile attempts to get the burner going. Clark bit his lower lip and glared at the burner. Chemistry was almost over, and he and Pete hadn't even been able to _start_ their lab.

Mrs. Tersa, Clark's frizzy-haired, absentminded Chemistry teacher, stopped at his lab station on her way around the room. With her goggles on, she looked like a gigantic insect.

"Still haven't got the burner, Kent?" Mrs. Tersa asked in her flighty voice. Clark mumbled a negative and blushed.

From the next table over, Lana turned and looked at him. Clark felt himself flush a bit more and clumsily dropped the sparker in his hands. Lana smiled kindly at him, then turned back to Whitney. Whitney was her lab partner, of course. Whitney shot Clark a venomous sneer when Lana couldn't see before turning his attention back to his flask.

Mrs. Tersa spoke again. "If you and Ross don't get that lit soon, you're both going to have to stay after school to finish." Her eyes goggled at Clark solemnly from behind the lab goggles. "Try to hurry it up."

"Alright," Clark mumbled, embarrassed. Mrs. Tersa wandered away as Pete came back. He had what would be their fourth hose for the gas in his hands. He looked at the still un-lit burner in disappointment.

"Ah, man," Pete sighed. Clark snuck another look at Lana and Whitney. Lana was laughing at something Whitney had said and happily stirring their boiling solution. Whitney had a lovesick half-smile on his face. Clark felt anger welling up inside of him.

"Mrs. Tersa said we'd have to stay after today if we didn't get this done in class," Clark told Pete.

Pete got a stricken look on his face. "After school? There's _no_ way." Pete looked left to right, making sure that no one was listening. "Do you think you could...you know...zap it?" he asked hopefully.

"Zap it?" Clark hissed incredulously. "You mean you want me to risk revealing my secret to the entire school, and thus end life as I know it, so that we won't have to stay after school for one day!"

Pete looked uncomfortable. Clark sighed and pushed his hair back from his forehead. "Alright, fine, but get between me and the class," Clark muttered. Pete grinned and moved.

Clark took a self-conscious look around the room. Mrs. Tersa was nearby, but her back was turned. Everyone else was engrossed with their labs. It was now or never. Clark bit his lip and shot an eyebeam out at the burner.

o-o-o-

Lex heard all about the explosion on Smallville's local news station.

He normally didn't waste his time with local news, but he had been flipping to CNN when Clark's face had popped onto his large plasma screen. Naturally, he left the channel where it was and turned up the volume.

A reporter was interviewing Clark, who had a long smear of ash on his cheek and was looking rattled. Behind him, the school was visible, along with two ambulances and the news broadcast van.

"-Yet you seem unhurt," the reporter was saying. Clark's face adopted a look that Lex recognized immediately. In fact, Lex had that expression memorized. It was the face Clark used when he was hiding something. It seemed to say, "Huh, what a weird coincidence." In fact, that was what Clark was saying out loud. Lex rolled his eyes. Clark was probably the worst liar Lex had ever met.

"I think it's because I was under the air conditioning vent," Clark postulated. "All of the escaped gas must have been blown away." Lex snorted at the television.

The interviewer said, "I see, I see." She looked at her notes. "And could you see how badly Mr. Ross and Mrs. Tersa were injured?" she asked.

Clark looked cornered. "Well, they just seemed kind of dazed," he said, sounding a little defensive. "They were a little singed. But it was nothing serious from what I could see."

The reporter turned to the camera and beamed. "Well, there you have it, folks. I'm Tina Springer, and I'm here live at Smallville High School. I've just been talking with Clark Kent, a junior here at Smallville High, whose Bunsen burner exploded earlier today, causing injury to another student and a faculty member. No other injuries have been reported, and the school remains intact. Thank you for speaking with me, Mr. Kent."

Clark looked at the camera uncomfortably. "No problem," he said, smiling half-heartedly at the reporter.

Tina Springer smiled. "And now, back to the studio! Tom, I hear you have some earth-shattering news about corn – "

The channel clicked to CNN. Lex bit his lip thoughtfully as he computed his net gains/losses in NASDAQ on autopilot. This created an interesting opportunity. The best way of getting someone's guard down was to surprise them.

Lex smirked as he made up his mind.

o-o-o-

Tuesday. The day after Monday. Incidentally, also the day after Clark Kent blew up his school and put two people in the hospital. Clark wasn't looking forward to school.

Clark was staring glumly at his blueberry pancakes. Mama Kent, who was bustling around in the kitchen, knew something was up from his stony silence.

"Don't worry, honey, it wasn't your fault," Mama Kent said soothingly as she came to stand behind Clark. Clark only bit his lip in reply. He felt doubly guilty. He hadn't told his parents the whole truth.

Clark didn't need another lecture on his superpowers, or the importance of his secret. He had been getting a lot of them lately. Didn't his parents think that he _knew_ how important his secret was? After all, it was _his_ life that would be changed the most if it got out.

"Clark, no one blames you. Just go to school and try your best, honey." Clark's mom put a soothing kiss on the top of Clark's head.

"I know Mom. And I will." He swallowed guiltily and stood.

"But then, why would they blame me?" asked Clark, in what he hoped was a nonchalant way. "Heh. I mean, it's not like _I _caused the explosion..." his mother looked at him blankly. Clark coughed into his fist.

Clark gathered his things and caught the bus. He spent the ride to school in silence, reflecting on the low-cut shirt Lana was wearing today and wondering if his Chem substitute would be hot.

o-o-o-

"Psst, Clark!"

Clark turned around to look at Whitney. He unfortunately sat behind him in Algebra II. Whitney leaned in close to Clark over his desk.

"I saw how you were looking at Lana yesterday," Whitney whispered. "Don't even think about trying to take her from me."

Clark recognized the dominant glint in Whitney's eyes. "Alright, whatever," Clark whispered back, turning around again.

"I mean it, Kent! I'm talking public humiliation. Don't even try," Whitney whispered menacingly.

Clark rolled his eyes. _Spare me the melodrama,_ Clark thought to himself (ironically). The bell rang and Clark allowed Whitney to shove past him roughly before going to Chemistry. Now that he was back at the "scene of the crime" Clark was getting a little nervous.

Clark slipped inside the Chemistry room and stopped dead.

Why was Lex here? Clark's eyes widened in surprise. Why was he writing "Mr. Luthor" across the board while smirking? When did _this_ happen!

"_Lex!"_ Clark squeaked. He threw his stuff down on his desk, which creaked a lot more than it should have. In the background, he heard Whitney gasp when he realized that Lex Luthor was in the classroom. Whispers hissed around the room like wildfire.

Clark went up to the teacher's desk. Lex had finished scrawling on the board, and turned to face Clark. Lex's eyebrows shot up as he looked Clark over.

"Clark. What a surprise," he said as he dusted off his hands.

o-o-o-o-o

AN: Cliffie! Mwa. Ha. Ha. If anyone wants to help me out with some fun stuff that could happen, leave a comment. I thought that Lex being at Clark's school could turn out very interesting for everyone but unfortunately I'm not certain where this story should go next.


	2. Day 1

Surprise!

AN: Thanks for your reviews! They really mean a lot...and they also really inspire me to write. No, I'm not hinting...ok, maybe a little. But really, thanks a lot to everyone who reviewed so far, namely Sonar, Smallvillegurl, Lishel Fracrium, orlandoandtom, Fire of the Dragons, WaffleNinja, Robyn6, and the Tribble Master. If I could I would make Lex give you all big hugs.

Disclaimer: Not mine.

o-o-o-o-

_Clark went up to the teacher's desk. Lex had finished scrawling on the board, and turned to face Clark. Lex's eyebrows shot up as he looked Clark over._

"_Clark. What a surprise," he said as he dusted off his hands._

o-o-o-o-

"Yeah, you could say that," Clark replied. Outside the classroom door, a small mob was forming. The news that Lex Luthor, in a blue dress shirt, designer pants, and $500 shoes, was teaching Chemistry II was traveling fast. Clark heard a girl squeal.

"What are you doing here?" Clark asked. Lex grinned deviously.

"I heard there was an opening," he said, leaning on the desk. "I thought I'd come by and see how you were doing."

Clark snorted. "Don't you have a multi-million dollar business to run in Metropolis?" he asked. Lex shook his head.

"Nope. Not this week, at least. My father decided to take over for a while." There was a glimmer of darkness in Lex's eyes. Clark decided to leave it at that.

"So you're qualified to teach science?" he asked. "I thought you had to have some sort of permit to teach high schoolers." Clark was having a foreboding feeling that he couldn't shake off.

"I'm qualified enough," Lex responded, with a mysterious little smile. Clark didn't really know how to respond to that, so he just nodded. Lex looked at him a moment longer, and then down at a list on the desk.

"So, which of these people should I give detentions?" he asked. Clark rolled his eyes.

"I don't know if you should be bullying people, Lex," he said. "You won't be my Chemistry teacher every day, and I think I'll get the blame for anything you do."

Lex sighed. "Ah, you're probably right. In that case, we probably shouldn't show that we're friends. Alright, student, take your seat." He smirked at Clark. Clark went to sit down just as the bell rang.

Lex closed the door amid the squeals of the mob outside in the hallway. The whispers in the classroom immediately died down.

"Alright, class," Lex said, flashing an amused smile. "Let's start with roll call."

Lex went through the roll, pausing once after Lana's name and once after Whitney's. Clark saw the look in his friend's eyes when he read off the jock's name, and couldn't help but feel a little nervous. Lex looked like he was plotting something.

Lex put aside the list of names, then addressed the class. "Hello. My name is Mr. Luthor." Whispers started around the room again. "I will be your substitute teacher for the rest of this week."

Lex waited for everyone to stop whispering. When it was completely silent again, Lex continued.

"Today, you are going to redo the experiments that were unfortunately destroyed yesterday." Lex's eyes scanned across Clark blandly. Some students snuck looks at him. "If you have any questions, feel free to ask me. Now go and start your labs."

Clark paired with Chloe, since Pete was gone. Due to Chloe's general competence, they made it through the entire period without any explosions. Just towards the end of the hour, Lex came to their lab to talk to them.

"So do you think I'm doing alright so far?" he asked. Clark, who was feeling very relieved that nothing strange had happened around Lex, nodded.

"No complaints from us," Clark said. Chloe practically vibrated next to him. She had spent the entire hour pouring theories into Clark's ears about why exactly _the Lex Luthor_ had taken time out of his extremely busy schedule to sub a high school class for a week. Clark had begged her not to poke and prod at him.

"Yes, you did a great job," Chloe said. "I guess that you're used to running things, being the head of Luthor Corp." Lex eyed Chloe and nodded. Chloe smiled a hundred-watt smile. "I'm sure there's _so_ much involved with running a business. I bet I wouldn't even have time to eat or sleep, if I was you."

Clark nudged Chloe's leg underneath the lab table. She was prying, in her specialized, indirect way. She kicked him back.

Lex smiled. "Well, from what I hear from Clark, you're just as dedicated to the Torch."

Chloe blushed but continued. "Yeah. It feels like I'm always looking for a story. I know that _I _wouldn't be able to take time off." Clark kicked Chloe again, feeling irritated. That last comment was an obvious challenge.

Lex raised an eyebrow. "It seems you never do. I'll talk to you later, Clark." With that he went back up to the front of the room. The bell rang, signaling the end of Chemistry.

Chloe and Clark went into the hallways together. Chloe was triumphant.

"Did you see?" she said. "He left as soon as I brought up his workload. He doesn't want us to know the real reason he's here!"

Clark rolled his eyes at his friend. "There is no 'real reason' he's here, Chloe. He probably had the week off, heard about the explosion, and thought it would be funny to surprise me."

Chloe scoffed. "Yeah, right. I don't think he's _that_ in love with you, Clark."

Clark blushed. "Shut up," he mumbled. He didn't know what else to add to that, so the two walked in silence for a while. He was extremely relieved. Nothing strange had happened today that would possibly tip Lex off about his secret.

"I'll see you at lunch," Chloe said finally. Clark nodded.

"Bye," he said, lost in thought.

o-o-o-

Chloe sighed to herself. Clark was so touchy sometimes. But other times, he would be the only person to look deeper. He had his faults, but...

...but he was obsessed with Lana. And don't forget, he only saw her as a friend. Chloe kicked the ground angrily.

Chloe missed Pete. She had called the Smallville Hospital the night before, and the receptionist had told her that he would be released tomorrow. She was definitely looking forward to being around someone who didn't make her so confused.

o-o-o-

Clark and Chloe met back up in front of the cafeteria. Clark gave her a small smile.

"What's for lunch today?" he said by way of greeting.

"Hmm...I think it's the mystery stew," Chloe replied. Clark groaned.

"Again? This'll be the eleventh time this month," he said. "I'm pretty sure there are laws against this sort of...treatment..."

Clark trailed off as he and Chloe entered the cafeteria and their jaws dropped. Long, white tables stretched across one entire wall of the spacious room. The tables were loaded with delicious looking food. There was even an entire table dedicated to desserts. The aroma of roast beef au jus hung in the air.

Chloe and Clark were still staring at everything in shock. Clark noticed a banner across one of the tables.

"LuthorCorp Catering," he read out loud. He exchanged a look with Chloe.

"Wow..." she said. The two were shoved aside by other students, who were less surprised and just ecstatic about the free food. Whitney shouldered past, elbowing Clark viciously in the side.

Clark froze for a moment, then his face broke into a huge grin. "This is great!" he yelled, ignoring Whitney completely. He had to consciously stop himself from using his superspeed to cut to the front of the line. Chloe was right after him.

The two took their platters of food out into the courtyard to eat. Chloe happily dug into some fried chicken.

"I don't care why Lex is here anymore," she announced in between bites. Clark, who was restraining himself from using superspeed again, nodded.

The first day had gone by without any disasters.

o-o-o-o-

AN: Hope you liked this chapter. I'll try to use some of you guys's suggestions next chapter...they really help me out, by the way. Please review!


	3. Day 2 Begins

Surprise

AN: Day 2. I hope you guys like this one – I've had a slight writer's blockwith it. And I know that my timeline for this story is completely skewed, but I'm going to call my laziness "creative license."

You might notice some of my real-life chemistry class shining through in this chapter. Finals are next week, so I don't think that there will be an update for about a week or so. I guess studying has even taken over my subconscious. :O

Disclaimer: Smallville isn't mine, but as I write this it _is_ going to be airing tonight. Season finale! Let's hope season five is better than four! (Kind of hard not to be)

o-o-o-o-

Lex was poking around in his father's old files. Lionel had an entire room dedicated to special cases in the Luthor mansion. It was a fairly large, ill-lit, windowless room that was completely filled with gray filing cases. Lionel thought that Lex was doing research on a potential investor of LuthorCorp. This was a complete lie.

Lex was doing something that he had always told himself he wouldn't. He pulled out a bulging manila folder marked "Kent, Clark," from a draw full of hundreds of identical folders. He held it in his hand and just looked at it for a while.

Lionel had ordered an investigation on Clark not too long ago. The agents had found several interesting things, or so Lionel had told Lex. Lex had stoutly refused to even entertain any thoughts of his friend being abnormal. Oh, he knew that Clark had a secret, and he fully intended to find out what it was, on Clark's terms or on his. However, he had felt that he didn't need Lionel's help.

Lex silenced a guilty voice in the back of his head. His curiosity barely overwhelmed his misgivings. However, being near Clark in a different environment, such as his school, presented so many opportunities that Lex couldn't pass it up.

With an odd feeling in his stomach, Lex opened the manila folder. Clark had been a bargaining chip between Lex and his father for a while, until Lionel had apparently lost interest. This was not the case, Lex saw, because there were reports that were dated from last Wednesday.

Lex spent the next two hours reading.

o-o-o-

"Good morning, class," Lex said, smiling and feeling like a true evil genius. He was feeling slightly apprehensive, but mostly satisfied. It was the way he usually felt before he pulled off his most successful plots. He was standing before the Chemistry II class, in a pale violet dress shirt and black pinstriped pants.

The class seemed to pick up on his predatory mood, because they all glanced each other uneasily.

Lex grinned, not realizing how devious he looked. "Today, you will be working on another lab assignment," he announced. There was soft groaning throughout the room. His smile didn't falter, and he looked at Clark directly.

"Hopefully, we'll all learn a lot," he said.

Clark felt his scalp prickle. He suddenly remembered why he had felt so ill at ease with the idea of Lex being around him at school. Lex was too smart and too observant.

Clark straightened up. Lex wouldn't find out anything if he didn't want him to! He met Lex's stare dead on, without flinching. Lex didn't change his expression.

"Directions are at the labs. You may begin," Lex said. His eyes slid off of Clark's and onto a sheet of paper on the desk.

Clark and Chloe set up their lab carefully. Clark was still feeling defiant for no reason.

Chloe leaned over and whispered in his ear.

"Lex is up to something. I just know it," she hissed. Her breath tickled Clark's ear. The smell of her shampoo drifted around Clark.

Usually, Clark would dismiss Chloe's accusation as just a crazy, baseless theory. However, the vibe that Lex had been giving off had been clear enough for even Clark to pick up on. Yes, Lex was up to something, and he was confident that whatever it was would work.

Clark was also absolutely certain that it had to with him. He wondered, in an offhand sort of way, if his theories were sound, or if hanging around with Chloe had given him stronger paranoia.

"I think you're right," Clark mumbled back, as he measured 50 mL of an unknown solution into a buret. The burets were long, thin glass tubes that stood vertical. The top was open and there were spigots at the bottom, so that the user could control to the drop the amount of fluid he or she wanted to draw. The lab was over titration, the method of finding the concentration of an unknown solution based on a controlled reaction. Chloe measured 50 mL of what was labeled hydrochloric acid into the other buret. She gave him a look.

"If _you_ picked up on it, Clark, then I know I wasn't just being imaginative," she murmured. Clark furrowed his brow.

"What's that supposed to mean?" Clark asked defensively. Chloe turned to him and gave him a look that spoke volumes.

"How are you doing?" Lex asked smoothly. Chloe jumped a little. Clark just barely managed to stop himself from jumping also. Lex had come up from behind them and was now standing at Clark's side. Chloe smiled brightly.

"Fine!" she chirped. "I don't remember this experiment on this semester's syllabus," she added. "I wish I would have had time to study for it."

For once, Clark was grateful for Chloe's talent of extracting information from people. Her natural curiosity and tact made her wonderful at it.

Lex smiled, but it didn't reach his eyes. "I'm sure you'll do fine. I'm not grading them, thank God."

Chloe persisted. "The syllabus said that this lab was scheduled for next week," she said, playing the role of an anxious student. "Does this mean that the test over titration has been moved up too?"

"Yes. Those were the instructions of your teacher," Lex said smoothly. Clark was beginning to feel silly for suspecting Lex of something.

Chloe barely paused for breath. "Why have they been moved up? We're still in the middle of Chapter 11."

"An excellent question," Lex said, studying her eyes. "Next week, a team of professionals will be coming in to investigate the gas lines thoroughly. They'll be in the way of the labs, so you have to do this one a week early." Lex cast his eyes down on their lab. He picked up the eyedropper from the phenolphthalein, which was what Clark and Chloe were using for their indicator.

"Your pipette is dirty," he observed. "You should replace it before the next class comes in." He turned to Chloe. "The pipettes are in the cabinet over there," he said, nodding to a cupboard on the other side of the room.

Chloe looked from Lex to Clark, who gave a small nod. She took one last measuring look at Lex before taking the offending pipette from Lex's hand and setting out for the cabinet.

"You can go ahead and start the titration," Lex suggested, leaning casually on the lab table.

Clark filled an Erlenmeyer flask with 250 mL of the unknown solution, which is a good amount of fluid. He then placed it under the spigot of the other buret, which contained a colorless solution that had been cleary labeled ".10 M HCl."

He looked up and found Lex watching him. Clark looked back down at the flask and opened the spigot.

The liquid in the buret rushed out and hit the unknown solution. There was a sudden explosion, and Clark stumbled back and was splashed with the solution and stray shards of glass.

Lex brought his hands up immediately, knowing that he would get hit, but also knowing that it would be suspicious if he didn't get hit. Students shrieked and dropped to the floor.

Lex brought down his arms, his shirt now streaked dark purple from the red color of the combined solutions. He gazed at Clark, who was laying on the ground and was partially soaked in the solution.

_Let's see what synthesized red meteor rock will do,_ Lex was thinking. _My father had such interesting notes on it._

Chloe had dropped the eyedropper, which shattered on the tile floor. Before shewas even thinking clearly again, she had spun around andwas runningtowardsClark. Lexlooked on with athoughtful expressionas she slapped his face and begged him to wake up.

o-o-o-o-

AN: Whoa, what a cruel place to leave off!

Please review! Hmm, will Lex's shirt be ripped in the next chapter? Hmm...I haven't decided yet...

Thanks so much to everyone who reviewed Chapter 2: Lishel Fracrium, orlandoandtom, mannah87 (daydreaming about how fun it would be to have Lex as a sub is what led to this story in the first place!), Fire of the Dragons, Sonar, DarkAngel135 (your prediction was right), Junior1985 (thanks for the favorite!), and The Tribble Master (you really helped inspire this chapter)!

PS – I just saw the finale, and Lex was so awesome! Wow... I'm going to make sure he gets really pissed off at _least_ once in this story.


End file.
